An integrated circuit (IC) may employ an external "local" processor for control of various elements on the IC. The IC may also employ an external memory element for storage of data received from, or transmitted to, the IC.
In conjunction with such a local system, a "host" processor may be used and it is therefor desirable to share the external memory between the local and host processors.
It is desirable to employ an ordinary random access memory (RAM) as the external memory element for cost reasons and to maintain compatibility with the purely local system.
Furthermore, it is desirable to be able to provide inter-processor communication using the shared RAM.